The invention is related to terahertz sources, and in particular to efficient terahertz sources based on difference-frequency generation in triply-resonant photonic resonators.
Nonlinear optical frequency conversion is widely used for the generation of light in parts of the spectrum for which there are no convenient sources. In particular, nonlinear processes are regarded as a promising route to generation of coherent radiation in the THz frequency range. Recently there has been a renewed interest in using cavity-enhanced nonlinear frequency conversion to enable greater flexibility and THz powers, as improved designs and fabrication techniques have paved the way for the realization of wavelength-scale cavities, thus allowing efficient conversion at increasingly low powers.